If you run an Ethernet connection to your ARC it will set up a wireless (not WiFi) connection to the Sub and rear SLs. To completely eliminate the use of WiFi you’d need a wired Sonos Controller too.

The ARC has center / right / left and Atmos speakers built in, the Front SLs will not be able to be connected to the ARC and used for 5.1. They could be added as a grouped room and used for music.

Thanks for the reply ans solution Mr.Stanley but could you please tell me what is Sonos Controller. 
 

If you want to connect the Sub to the Arc or use the two One SLs as left and right rear surround speakers, you need to leave WiFi enabled on the Arc because it uses its own WiFi signal to communicate wirelessly to the Sub and surround speakers.

The “Sonos Controller” usually refers to the Sonos app on your phone, tablet, or computer.

NOTE: You must use the Sonos S2 app on a iOS or Android device to set up the Arc. It cannot be set up using the Sonos app/controller on a computer.

To nit-pick a bit but in an attempt to avoid confusion.

The SonosNet - WiFi confusion in the Sonos system causes a lot of misunderstanding. They use the same frequencies but the signal formatting is not compatible.

The Controller’s Settings Menu says Disable WiFi but it actually means disable the radio. You select WiFi off and the radios used for both WiFi and SonosNet are disabled.

If you do net enter the SSID and password for WiFi then WiFi won’t be used but SonosNet will.

I believe you can use the mobile app on a device that is connected via an Ethernet dongle, don’t have one to confirm that though.

Controller:  https://support.sonos.com/s/downloads?language=en_US